I always clean the brush off first before I even start spraying it on the car. I hate using the brush, if you see closely, I have my wash mitt on the roof of the car (Brown glove).
I'm only using the brush to lay over the soap so I can wipe/spread it with my washing mitt and then hose it off.
Over here, we aren't allowed to use our own buckets, the management asks us to leave if we use a bucket!